SYSTEMATICS OF ECONOMICALLY IMPORTANT MARINE-ALGAE - A CANADIAN PERSPECTIVE

Marine algae of economic importance encompass species of positive value, such as seaweeds harvested for food or hydrocolloid extractives, and species with negative effect. such as toxic phytoplankton or nuisance macrophytes. Only a small part of the global algal resource is obtained in Canada, and the overall benefit to the nation's economy is relatively minor, but there exists the potential for further development of useful species. On the other hand, the negative effects of toxic microalgae are increasing, in the form of losses to the shellfish fishery and aquaculture industry and the cost of providing toxicity-testing and phytoplankton-monitoring services. It is obvious that effective utilization of valuable algae, or defense against undesirable ones, must be attended by sound taxonomy to ensure that algae of interest are correctly identified and recognizable. However, the algae present particular problems to systematists, a major one being the variety of life histories, which may involve independent and conspicuous dissimilar phases. In addition, many algae are phenotypically highly variable in response to environment, which is often insufficiently appreciated. The converse situation also exists, in that morphologically similar species are sometimes regarded as a single entity. Algal taxonomists should strive to determine which variations are genetic and therefore taxonomically significant. To illustrate these points, we review recent taxonomic studies on some algal genera of present or potential economic importance in Canada.